In the music industry, media for sound recording were changed from records to CDs, and analog recording was abruptly changed to digital recording in the 1980s. Further, large-capacity DVDs as media for recording information including video images have also been penetrating the market. Dramatic improvements in storage capacity have also been achieved in the field of magnetic recording materials, typified by cassette tapes, by adopting a vertical magnetic recording system, or by developing magneto-optic recording media; as a result, random access has become feasible. In the field of motion pictures, an analog soundtrack has been used as a sound-recording system since the invention of talk-type film (talkie) by De Forest et al. in the U.S. in the 1920s. As to sound-recording in the motion picture industry, a noise reduction system was developed and released by Dolby Laboratories, Inc., and high-quality analog audio recordings are produced at present. In addition, from the second half of the 1980s to the first half of the 1990s, several formats for digitizing motion picture sound, including the Dolby Stereo SR-D system by Dolby Laboratories, Inc., and the SDDS system by Sony Corporation, were released, and the number of film screenings with digital sound has been growing. However, the formats permitting the use of both analog sound and digital sound have been adopted, up to the present, as insurance against reproduction failure by accidental impairments of digital recording information, so at present, analog sound is used for audio recording in almost all motion pictures.
In the method of reading information from such an analog soundtrack, information on light signals modulated by transmission through the area-modulated analog soundtrack region is detected as sound information with a phototube having high sensitivity in the infrared region of 750 nm to 850 nm, or with a recent silicon-type photodiode having its absorption maximum in the region of 900 mm, and the optical signals detected are converted into electrical signals and reproduced as sound information for film screening. Since the detection wavelength is in the infrared region, the sound information is required to be recorded as silver images on an analog soundtrack, and even today's colorized motion picture films retain silver images on their individual analog soundtracks. In processing motion picture films, therefore, a special processing step for forming silver images, by applying a silver developer to the analog soundtrack regions alone, is still carried out after the process steps for processing the image regions. Such elaborate, troublesome processing is a considerable burden for processing laboratories.
Against this backdrop, the dye track system, in which sound information is recorded as developed cyan dye, but not developed silver, on an analog soundtrack, by use of a red LED as an exciter, was presented at the SMPTE Technical Conference and World Media Expo held in October 1996. This report described a soundtrack reading mechanism that used a red LED illumination source, and thereby made it possible to eliminate the need for the aforementioned special processing step for forming silver images through application of a developer. Up to the present, red LED analog readers have been aggressively sold. However, as is the case with digital formats, it is necessary to address a requirement that equipment, including red LEDs and electrical signal amplifiers to amplify sound that is converted into electronic signal, must be provided for projectors installed in individual theaters. Despite the necessity, the provision of such equipment in all theaters is making slow progress. With consideration given to theaters into which the equipment has not yet been introduced, a temporary changeover to a high-magenta soundtrack capable of sharing a sound negative with a cyan dye track is recommended and regarded as a preliminary stage of the changeover to cyan dye sound, and thus a silver-retaining processing (i.e. a processing to form silver soundtrack) is carried out even now.
With the intention to achieve simple processing of motion picture films in processing laboratories without requiring the introduction of equipment into theaters and enabling omission of the development of analog soundtracks by application of a developer thereto (hereinafter also referred to as “the application development of soundtracks”), arts of recording analog sound information with couplers capable of forming infrared-absorbing-dyes are disclosed in JP-A-63-143546 (“JP-A” means unexamined published Japanese patent application), JP-A-11-282106, JP-A-2003-228155, and U.S. Pat. No. 5,034,544. In addition, arts of enabling retention of sound information as silver images in a soundtrack region by incorporation of bleach inhibitors or bleach inhibitor-releasing couplers, thereby omitting the application development of soundtracks, are disclosed in U.S. Pat. Nos. 3,705,208, 3,705,799, 3,705,800, 3,705,801, 3,705,802, 3,705,803, 3,737,312, and 3,749,572, and in JP-A-49-103629, JP-A-51-077334, JP-A-51-151134, JP-A-53-125836, and JP-A-55-110242. These arts are very excellent arts for simplification of processing.
On the other hand, cinematographic positive films for screening, though they vary from theater to theater, are prepared in very large quantities by a processing laboratory and sent out to respective theaters, so it is required that the processing of motion picture films in a processing laboratory be performed not only in a simplified process but also in very large quantities within a short time period. Accordingly, in addition to the aforementioned arts of simplifying the processing process, there is a further need to develop the art of reducing the time for preparation of enormous numbers of motion picture films, by increasing hourly film production through reduction in the exposure and processing time of the films. To increase hourly film production, it is required that the linear speed in each processing step be improved, in addition to elimination of the need for the application development of analog soundtracks. In addition to the application development of analog soundtracks, the development process of positive cinematographic photosensitive materials is also a rate-determining step for the increase in processing speed, so improvements therein have been expected.
Cinematography, which is an application of silver halide photography, is a method of obtaining moving images by sequential 24-sheets-per-second projection of elaborate still images, and cinematography delivers overwhelmingly high-quality images, compared with other methods for reproducing moving images. By utilizing the high quality of cinematographic images as an asset, the images can be easily projected on a giant screen. As such, these moving images are suitable for simultaneous viewing by a large number of people. Under these circumstances, numerous theaters having motion picture projecting apparatus and large seating capacity have been built. On the other hand, explosive developments of electronic technology and information processing technology in recent years have enabled the advent of projectors using DMD devices of Texas Instrument Incorporated, D-ILA devices of Hughes-JVC Technology Corp., or high-definition liquid crystal devices of Sony Corporation, to provide more convenient tools for reproducing moving images of near-motion-picture quality. Therefore, it is also required that convenience and facilitation, especially simplification and time-reduction of operations in photo laboratories, be conferred upon motion picture films while maintaining their high image qualities.
As one factor responsible for the complexity and difficulty of developing operations of silver halide photosensitive materials for use in motion-picture projection (screening), the presence of development for sound can be cited.
In motion pictures, imagery and sound are required to be in synchrony. Since the invention of the motion picture, various attempts to accompany pictures with sound have been made. Study was especially made to combine motion pictures with the analog recording technology invented as a sound recording-and-reproduction method at the same period, but techniques in those days failed to provide satisfactory synchronization. As such, this combination has not been brought to commercialization. To achieve synchronization with simplicity and reliability, ideally, image information and sound information should be recorded concurrently on projection films. Against the backdrop as mentioned above, the technique of optically recording sound on projection films was developed in the 1920s. The dominant projection films in those days were black-and-white (B/W) photosensitive materials forming images of developed silver, and, on the apparatus part also, the reading of sound signals at the time of projection was made on the premise that the signals were recorded as silver images. The developed silver absorbs light in a wide wavelength region, from ultraviolet light to infrared light, so the reading apparatus has no particular restriction as to the wavelength region for reading. Therefore, the reading apparatus used was one having a maximum sensitivity in the region of 800 nm to 900 nm, which was easy to commercialize with the techniques of that time.
Color-developed dyes forming color images in silver halide color photosensitive materials for projection purpose, which material were commercialized from then on, have no absorption in the near infrared region of 800 to 900 nm utilized by sound-signal readers. However, no change was made to the systems for reading sound signals from the time of development to the present day, and sound signals are still recorded as silver images in the current silver halide color photosensitive materials for projection purposes. On the other hand, the developed silver in the image areas of silver halide color photosensitive materials for projection purposes is removed in a processing step, out of necessity to enhance color purity.
As mentioned above, dye images having no need for silver images and sound signals to be formed of silver images are both present on the same silver halide color photosensitive material for use in projection. Thus, the development-processing process of silver halide color photosensitive materials for projection purposes becomes complicated, because application of a special developer to the sound signal-recorded region (the so-called soundtrack) alone becomes necessary halfway through the processing, with the result that this operation becomes burdensome to photo laboratories.
On the other hand, simplification of the development-processing process is a very important problem from the viewpoint of environmental conservation by resource-savings, in addition to reduction of loads imposed on photo laboratories. Much research has therefore been conducted, and the fruits thereof have been introduced into the market. For instance, the standard development process of negative-positive silver halide color photosensitive materials for projection purposes, which in 1990 had 14 steps (the development process disclosed as ECP-2A by Eastman Kodak Company), was reduced to 12 steps at the end of the 1990s (the development process disclosed as ECP-2D by Eastman Kodak Company). However, the development process of silver halide color photographic printing paper, aiming to show pictures as in the case of silver halide color photosensitive materials for projection purposes, had only three steps. Viewed from this angle, it can be said that the current 12 steps are still too many.
One factor responsible for the high number of processing steps a silver halide color photosensitive material for use in projection is required to undergo is the aforementioned complex processing intended for the soundtrack formation with silver images. Therefore, methods of forming soundtracks through the same processing steps that are applied for the formation of dye images have been studied.
Examples of representative studies include methods of inhibiting, imagewise, the bleaching of silver images by use of bleach-inhibitor-releasing couplers to form silver-image soundtracks themselves, which are disclosed, e.g., in U.S. Pat. Nos. 3,705,208, 3,705,799, 3,705,800, 3,705,801, 3,705,802, 3,705,803, 3,737,312, and 3,749,572, and in JP-A-49-103629, JP-A-51-077334, JP-A-51-151134, JP-A-53-125836, and JP-A-55-110242.
Other cited examples are methods of using infrared-absorbing-dye-forming couplers, as disclosed, e.g., in U.S. Pat. Nos. 2,266,452, 3,458,315, 4,250,251, and 5,030,544, and in JP-A-63-143546, and JP-A-11-282106. These are the art of forming soundtracks from developed dyes whose absorption is in the near infrared region required by the available sound readers.
Known alternative measures include techniques for modifying sound-signal readers, but not on the photosensitive material part, so as to read sound signals recorded by a color-developed dye used for forming dye images. A representative example thereof is the technique of forming soundtracks from developed cyan dyes, which is referred to as “cyan dye sound” (details of which were presented in a paper entitled “Red LED Reproduction of Cyan Stereo Variable Area Dye Tracks” at the SMPTE Technical Conference and World Media Expo (1996)). This technique permits the use of preexisting color photosensitive materials for projection purposes, and further, the adoption thereof requires photo laboratories to add almost no modifications to their existing facilities. However, such a technique requires the modification of sound readers. Although cyan-dye-sound adaptations of the sound readers attached to the projectors already on the market have been under way, the changeover from all silver-image soundtracks to cyan-dye soundtracks requires that modifications be made to all projectors, so it is far from practical. In fact, both traditional sound readers utilizing the infrared region and cyan-dye-sound-capable sound readers utilizing cyan dye images are present together on the current market.
The traditional sound readers differ from the cyan-dye-sound-capable readers in performance, so it is required to form soundtracks corresponding individually to these two types of readers. In each photo laboratory, therefore, photofinishing for supplying cyan-dye soundtracks to theaters having cyan-dye-sound-capable equipment, and photofinishing for supplying traditional soundtracks to theaters having conventional-type equipment, are required to be performed separately; as a result, the operations become more and more complicated. Aiming to solve such a problem, the method of making a change to the hue of traditional soundtracks, to support both types of readers (a high-magenta soundtrack method), was presented. Even when this method is adopted, however, the loads imposed on photo laboratories remain the same as heretofore, because the recording of sound information therein is performed with silver images.